To study interaction between tumor cells and stromal elements, we established carcinoma cell line as well as tumor-derived and skin fibroblast cultures from four patients with squamous cell carcinoma of the head and neck. For the characterization of the tumor cell lines we a) determined population doubling times, b) assessed morphological features by light and electron microscopy, c) investigated the expression of typical markers by immunohistochemistry, including various intermediate filaments and surface antigens, d) compared these findings with expression patterns in the respective original tumor specimens, e) evaluated p53 mutations in tumor specimens and cell lines, f) performed chromosome analysis, g) investigated the tumorigenicity in athymic mice, and h) tested the formation of both tumor and mixed tumor-fibroblast multicellular spheroids. Tumor cell cultures were considered established cell lines when maintained and passaged over a period of two years after primary explanation. The in vitro morphology of the cell lines showed well preserved characteristics of squamous cell carcinoma, and electron microscopy as well as immunohistochemistry revealed their squamous type of differentiation. All cell lines presented the same p53 genotype as the respective original tumors. Furthermore, they were successfully xenotransplanted into nude mice and formed both pure and mixed three dimensional spheroids. This experimental model allows the in vitro and in vivo investigation of various tumor-fibroblast interactions.

Primary malignant fibrous histiocytoma (MFH) exhibits an extremely adverse prognosis. Investigations into the principles determining the biological aggressiveness of this cardiac tumor would be facilitated by an appropriate in vitro model. Therefore, we report on the first permanent cell line (MFH-H), derived from a human cardiac MFH. The original tumor had shown coexpression of cytoskeletal filaments typical of mesenchymal (vimentin), epithelial (cytokeratins) and neurogenic (neurofilaments) differentiation. This potential for multidirectional differentiation was observed in the MFH-H cell line as well and indicated marked plasticity of gene activation acquired during the process of neoplastic transformation. Pronounced genetic alterations also became evident from cytogenetic analysis, which revealed a highly variant karyotype with multiple numeric and structural chromosomal aberrations. Secretion of G-CSF, GM-CSF and M-CSF was shown to be another feature of deregulated gene expression in MFH-H cells. Direct autocrine effects of their hematopoietic growth factors, however, were precluded by the lack of the corresponding receptors. In conclusion, the cell line MFH-H will provide an appropriate in vitro model to analyze the biological properties of this cardiac malignancy in more detail, especially with regard to a possible immunomodulating capacity of MFH-derived hematopoietic growth factors.

This study describes characteristics of two newly established cell lines (OSC-1 and OSC-2), derived from two oesophageal squamous cell carcinomas. Morphologically, OSC-1 cells and OSC-2 cells grew in epithelial cobblestone patterns with cells piling up to 4 cells. Ultrastructurally, both cell lines showed formation of desmosomes; however, tonofilaments were only formed by OSC-2 cells. Immunohistochemical investigations revealed coexpression of vimentin and cytokeratin in OSC-1 cells and OSC-2 cells. A cytokeratin subtype typical for mature squamous epithelia (cytokeratin 13) was expressed only in OSC-2 cells. OSC-1 cells showed tumour formation in nude mice, whereas OSC-2 cells did not. Cytogenetic analysis revealed that OSC-1 cells had a hyperdiploid karyotype and OSC-2 cells had a near-triploid karyotype. In both cell lines, the formation of multicellular spheroids could be induced. In conclusion, in comparison with OSC-2 cells the OSC-1 cells were characterized by a poorer degree of differentiation and by a more aggressive growth behaviour in vivo.

The chromophobe renal cell carcinoma is a distinct type of renal cancer presumably derived from the intercalated cell of the collecting duct system and exhibiting a better prognosis than other types of renal cell carcinoma. Chromophobe carcinomas can be separated from other types of renal cell carcinoma by their characteristic cytomorphology, ultrastructural appearance, cytoskeletal architecture, and cytogenetic aberrations. As no permanent cell line of the chromophobe tumor type has previously been described, we are the first to report on the successful establishment and characterization of two divergent permanent cell lines, ie, chrompho-A and chrompho-B, derived from the same chromophobe renal cell carcinoma. With immunocytochemistry, two-dimensional gel electrophoresis, and Western blot, chrompho-A and chrompho-B exclusively exhibited cytokeratins (Nos. 7, 8, 18, and 19) but not vimentin. Ultrastructural studies revealed numerous cytoplasmic microvesicles as well as coated vesicles that are known to be characteristic features of the intercalated cell. Chrompho-B cells exhibited a shorter mean population doubling time (tD = 43 hours) than chrompho-A cells (tD = 51 hours). Both cell lines failed to produce tumors in nude mice with the subrenal capsule assay. Cytogenetic analyses revealed hyperdiploid chromosome numbers in both cell lines with telomeric associations as well as numeric aberrations known from chromophobe renal cell carcinomas in vivo.